All you have to do is head to Settings -> General -> Restrictions and turn the YouTube app OFF. This will cause all video links to launch the YouTube web app, which I definitely prefer over the lackluster native app. Relevant search results show up faster in the web app and I find it much easier to share URLs by tapping in the URL bar instead of generating an e-mail in the native app and copying the URL from there.

Oh, and while you're still in Restrictions, you should probably also turn Ping off because it's, well, completely useless.